In IsUserDefinedConversion try to recover from RequireCompleteType returning true.

Fixes an assertion later on, rdar://9122862 & http://llvm.org/PR9460.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130000 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed